accordhybrid- Ummmm, the b16a has a very good bottom end. It comes from the factory pretty well balanced and is the only production engine that I can think of that has a near perfect rod-stroke ratio. Perfect R/S ratio is 1.75:1 and the b16a is a 1.74:1 so you see in stock form the bottom end is capable of around 9000 rpms safely IMO. Anything over that and I would have to agree that the rods will need at the least a bolt upgrade.